Titanium Alloys: Advantages and Applications in Aerospace Engineering

Titanium alloys and titanium-based composite materials are widely used in the aerospace and aerospace engine fields due to their high specific strength, high temperature resistance, corrosion resistance, and excellent compatibility. Titanium alloys have a density of approximately 4.5 grams per cubic centimeter, similar to medium-strength steel in terms of strength but only 60% of the weight of medium-strength steel. This results in a nearly twofold increase in specific strength, which helps reduce the weight of aircraft structures. Titanium alloys can effectively replace aluminum alloys and stainless steel, which are not suitable for high-temperature applications. For instance, Ti-6Al-4V products can operate for an extended period at 350°C, while TC11 can work at 500°C. Compared to hard aluminum and structural steel, titanium alloys exhibit superior corrosion resistance. Titanium alloys have various classifications and wide-ranging applications, including corrosion-resistant titanium alloys, heat-resistant titanium alloys, high-strength titanium alloys, low-temperature titanium alloys, powder metallurgy titanium alloys, and functional titanium alloys. Common forms of titanium alloys include plates, rods, tubes, forgings, wires, and castings, with plates, rods, and tubes accounting for approximately 85% of titanium material production in China.

Titanium Alloy Industry Chain

The titanium industry chain can be broadly divided into two segments: one is the non-ferrous metal sector chain, which includes titanium ore → titanium sponge → titanium ingot → titanium material; the other is the chemical industry chain, which involves titanium ore → titanium dioxide. These two chains are closely connected in the upstream but relatively independent in the middle and downstream stages. The non-ferrous metal chain can be divided into three main parts from top to bottom: 1) Upstream includes titanium iron ore, ilmenite, and other titanium ore resources, as well as synthetic rutile, titanium slag, and titanium tetrachloride produced from processing titanium iron ore. 2) The middle segment is mainly divided into two parts: one is the reduction of titanium tetrachloride to produce titanium sponge, and the other is melting the titanium sponge to cast titanium ingots, which are further processed into forging, rods, plates, tubes, wires, and other titanium materials. 3) The downstream stage involves further processing of titanium materials according to the requirements of aviation, aerospace, petrochemicals, nuclear power, naval vessels, desalination, automobiles, sports medicine, and other fields.

Core Barrier: Titanium Material Processing

Looking at the entire industry chain, the core barrier in the titanium material industry lies not in upstream resources or midstream smelting but in the processing capability of titanium materials, especially in the research and manufacturing processes of high-end titanium materials.

Challenges in Titanium Material Processing

High-end titanium materials are often produced using the Vacuum Arc Remelting (VAR) technique. The VAR technique utilizes a consumable electrode produced in an induction furnace in a vacuum or inert gas environment for controlled AC arc heating and melting. This process has strict requirements for the heat source, as temperature non-uniformity in the molten pool can lead to uneven composition, inconsistent structure, and potential solidification defects, which can affect the performance of the final product. For high-end titanium alloys, the ingots usually require three rounds of VAR melting to achieve uniform composition and low defect rates.